Pressure-applying air pad



June 25, 1929. Q, WCHALK 1,718,300

PRESSURE APPLYING AIR PAD Filed Nov. 3, 1928 Jnvenfor: Otto Michalk.

Patented June 25, 1929. I

NITED STATES OTTO MICHALK, OF FREITAL, NEAR DRESDEN, GERMANY.

PRESSURE-MPLYING AIR PAD.

Application filed November 3, 1928, Serial No. 316,924, and in GermanySeptember 3, 1928.

In the manufacture of shoes by the cementing method, more particularlyfancy shoes, air pressure pads .are almost exclusively used. Theycontain a 'flat rubber bladder sewn into a leather bag. The use of thesepressure applying pads has the disadvantage that in consequence of thepressing pressure the heel cap of the shoe is forced out sideways at itsperiphery and that the sole is forced up at the toe, the ball and theheel of the shoe. This entails additional work during the manufacturingprocess, involving additional expanse, in order to make the shoesalable.

The present invention overcomes this difficulty by the sole which is tobe stuck on not being cemented on at all at the heel part in the sameoperation and the forcing up of the sole at its edges being prevented.The pressure-applying pad therefore extends only along the sole and theinstep of the shoe, thus ending in front of the heel. In addition tothis the pressure-applying pad is stiffened over the rubber bladder by areinforcing sole which is chamfered 01f at the end of the ball, thusproviding a gradual transition to the softer part of the bag of the padat the instep. The stilfening sole mighthowever be extended under theinstep by a sole of soft leather joined to it in a suitable manner bycementing the parts together.

The accompanying drawing shows a constructional example of theinvention, Fig. 1' being a plan View of the pressure applyingpad with asole indicated above it.

Fig. 2 a logitudinal section through the pad on line 2 2' of Fig. 1, andI Fig-3 a cross-section on line 3-3 of Fig. 1

Fig. .4 is a longitudinal section similar to F ig. 2 through anotherconstructional form.

Thepressure-applying air pad consists of the leather bag formed by thelayers f, f and the edge strip h, marginally sewn together and of arubber bladder inserted in the hollow space between them and having avalve extending to the outside. The pad bag is usually reinforced by anupper layer of leather 2'. In order that the heel portion shall not havepressure applied to it during the cementing operation, the pad bagextends only three-quarters of the length of the sole, namely up to theline b?) in Fig. 1, thus endingimmediately adjacent the heel or the heelpart d of the sole d. The heel part at will therefore not be cementedon, but maybe nailed or otherwise secured to the sole. On theside facingthe outer sole the pressure applying pad is stiffened by a leatherinsertion is which is chamfered off at the end of the ball point, saybetween the lines w-:n and yy, so that it merges gradually into the partof the pad bag under the ortion c of the sole and which forms the instepof the shoe. This insertion may be placed inside the bag, i. e., betweenthe two protective covers f and e or on the outside of the bag. When thepressure is applied, the insertion is prevents the edge Z of the sole dfrom being pressed against the shoe m.

In order to give the pressure-applying bag a flat surface, the insertionis may be coning layer for said bag, all the said bag, blad del', saidlayer being of a length to extend over the sole part and instep of theshoe only, and to end short of the'heel part, substantially asdescribed.

2. A pressure-applying air pad for. shoe cementing air presses,comprising a leather bag, a rubber bladder enclosed in said bag,

means forinflating said bladder, a reinforcing layer for said bag, thesaid bag, bladder, and layer being of a length to extend over the solepart and instep of the shoe only,

and to end short of theheel part, and an additional stiffening leatherlayer arranged to extend over the sole part of the shoe and chamferedoff at a point coinciding with the end of the ball of the shoe,substantially as described.

3. A. pressure-applying air pad for shoe cementing air presses,comprising a leather bag, a rubber bladder enclosed in said ranged toextend over the sole part of the bag, means for infiatin said bladder, areinshoe and chamfered off at a point coinciding forcing layer for saiha th'esaid bag, with the'end of the ball of the shoe, and a m bladderand layer being 0 a lengthto exsoft leather extension applied to saidstiffen- 5 tend over the sole part and instep of the ing leather layer,substantially as described. shoe only, and to end short of the heelpart, In testimony whereof I aflix my signature. an additionalstiffening leather layer ar- OTTO MICHALK.

